The objective of this research is to devise safe and efficient targeted synthetic gene vectors for parenteral administration in animals. The dogma guiding our plan is that processes and molecular strategies employed by viruses in the infection process can be recapitulated in less complicated molecules. When these simpler molecules are correctly assembled with plasmid DNA in a nanolipoparticle (NLP), an efficient gene delivery system will be created. There are three major activities in the program: (a) synthesis of novel components, (b) assembly of the components into a small diameter, stable particle and (c) characterization of the performance of the assembled components in cells and animals. The plan is organized to accomplish four specific aims that are based upon testable hypotheses that are fully articulated in the application. Specific aim (1): To devise lipids that change structure either at low pH or under reducing conditions, that can be employed to package the DNA in a NLP, assist delivery in vivo and mediate rapid, efficient cytoplasmic entry after internalization into cells. Specific aim (2): To devise processes and techniques to assemble the components required for efficient gene transfer into a stable NLP with a diameter <100 nm. Specific aim (3): To create a macromolecular motor that can be attached to DNA and mediate transport of the DNA along microtubules toward the nucleus. Specific aim (4): To characterize the safety and gene transfer efficiency of targeted NLPs in cells and animals. Two targets will be investigated: (1) targeting with epidermal growth factor to hepatocytes in normal liver after tail vein administration of a low volume formulation. (2) targeting with an oligosaccharide from hyaluronan to CD44 expressing tumors in mice. Completion of these specific aims will lead to a targeted, biodegradable synthetic gene vector with an in vivo gene transfer efficiency approaching that of current viral vectors but with a better safety profile. This improved gene carrier will enable successful gene therapy for a variety of currently untreatable genetic and neoplastic diseases.